Guarantee a note personally sort of defeats the purpose of utilizing a remote entity, at least for the liability created by the note.  

Should I try to have him fill out a W9 and sign some sort of contract since money over $600 is being exchanged for services? 

These are just a few starting places that could help you sort through your plans! 

I'd refer them to petscreening.com and let them sort out the ESA letter.

You will probably have some sort of limit regarding mold/medical, but thee things can turn into a mess, trust me, I manage a lot of units and have done so for almost 30 years. 

I figure if I charged any sort of deposit, they will leave the place dirty enough to justify the extra work to clean it back up with the deposit money.22 houses total. 

A properly structured syndicated offering will be an LLC as is, therefore, from an asset protection standpoint, there is very little point to forming an LLC just to participate on the LP side.Now, if you are trying to pull partnership money and charge the partnership a management fee, which sort of makes you a feeder fund into the syndication, then there are a whole host of questions for an attorney. 

Most syndication business plans involve a value-add strategy of some sort. 

Am I issued some sort of deed after 3 years of paying?

I almost wonder if this question is a plant of some sort just to gauge the types of responses it would generate, so I'll take the bait in the even that this is a bot or troll (full disclosure, my career is not in any way related to the success or failure of the RE market).